解析單元法外文翻譯

1、<p><b>　　附件</b></p><p>　　Analytic Element Method</p><p>　　The research in groundwater flow is aimed at producing tools capable of accurate and efficient modeling of large region

2、al systems of groundwater flow. These systems often consist of many water-bearing layers,called aquifers, that are separated by leaky layers that resist flow, but are not impermeable. Most groundwater enters such aquifer

3、 systems via the uppermost layer in the form of infiltration from rainfall. Accurate prediction of contaminant movement and analysis of the zone to be protected </p><p>　　The method developed at this departm

4、ent for such regional groundwater modeling is the Analytic Element Method. The two most important applications of this method, to problems of the kind described above,are the Metropolitan Groundwater Model (Metro Model)

5、of the Twin Cities Groundwater Basin (see http://www.pca.state.mn.us/water/groundwater/metromodel.html), and the Dutch National Groundwater Model NAGROM.</p><p>　　The Analytic Element Method is based upon th

6、e superposition of analytic functions,called analytic elements, which can be adjusted to meet certain boundary conditions. The method can be applied to general problems of two-dimensional and three-dimensional flow. Curr

7、ent research focuses on the accurate modeling of leakage between aquifers, the combination of two-dimensional and three-dimensional elements in large regional models, and the so-called superblock approach which makes it

8、possible to crea</p><p>　　The two-dimensional Analytic Elements are developed using an approach known as Wirtinger Calculus, which is based on a change of variables that permits all analysis to be</p>

9、<p>　　carried out in the complex domain, regardless of the nature of the vector field that describes the flow. The vector field in groundwater flow represents the discharge in each aquifer; the properties of this v

10、ector field, i.e., its divergence and curl, depend on the nature of the flow. The Analytic Elements are selected such that some create a vector field that is divergence-free and irrotational (Laplace Field), others creat

11、e divergence, and still others rotation.</p><p>　　Figure 1: Contours of constant displacement components for</p><p>　　a uniformly stressed elastic medium with inclusions of different</p>

12、<p>　　elastic properties. These calculations were performed using the</p><p>　　Analytic Element Method, initially developed for groundwater</p><p><b>　　flow.</b></p><

13、p>　　Figure 2: Capture zone formed by streamlines emanating from a well for a waste repository. The area containing waste is surrounded by a slurry wall (a trench filled with a material with high resistance to flow). A

14、 small well inside the area captures whatever rainfall enters the area and may be polluted. The figure on the left corresponds to the case for which the wall is designed, whereas the figure on the right shows the case wh

15、en a small opening exists, causing significant leakage to occur. It</p><p>　　Acoustic Emission Monitoring</p><p>　　A common feature of failure for rock is the development of microcracking, which

16、 releases energy in the form of elastic waves called acoustic emission (AE). The AE technique can be used to monitor the evolution of damage, through the entire volume, at various stages of loading. The locations of AE p

17、rovide a picture that forms a basis for the justification of mechanical models of damage and failure. Indeed, a physical interpretation of the data may be used to define a characteristic length of a qu</p><p&g

18、t;　　Figure 3: Locations of acoustic emis-</p><p>　　sion up to about 95% of the peak stress</p><p>　　(blue) and around peak stress (red) in a</p><p>　　beam test with a Berea Sandston

19、e.</p><p>　　Microcracking was more or less random</p><p>　　prior to peak stress, but a localized region</p><p>　　can clearly be identified at peak stress.</p><p>　　Non

20、destructive Pavement Characterization</p><p>　　With our highway systems deteriorating, their timely monitoring and repairs are essential. Currently, a number of seismic testing devices such as the falling we

21、ight deflectometer are available for non-intrusive pavement diagnosis. The effectiveness of such remote sensing tools remains intrinsically hampered, however, by the difficulty of data interpretation. In this investigati

22、on, an advanced back-analysis is developed for delineating the pavement subgrade profile from FWD measurements. The inve</p><p>　　and a viscoelastodynamic pavement model as a predictive device. To expose the

23、 pavement’s resonance and stiffness characteristics, ground deflection data are interpreted in terms of suitable frequency response functions. Robustness of the back-analysis is improved via (i) an integral data sampling

24、 scheme, (ii) noise injection technique used in the neural network development, and (iii) low-pass filtering of the seismic records, employed to minimize the masking effect of lateral wave reflections on</p><p

25、>　　Figure 4: Comparison of the theoretical</p><p>　　frequency response function, produced by the back-</p><p>　　analysis, with the field measurements taken at the</p><p>　　Minnes

26、ota Road Testing facility.</p><p>　　Longitudinal Cracking of Flexible Pavements</p><p>　　The cracking along the wheel path (longitudinal) is of major concern in flexible pavements. These cracks

27、originate at the surface of the asphalt layer and often terminate before reaching the base of the pavement. To gain an insight into the potential mechanisms of the formation of longitudinal cracking, numerical simulation

28、s are carried out using the computer code ABAQUS. To incorporate the actual non-uniform and complex normal/shear tire load, a fully three-dimensional elastic layered system is</p><p>　　The presence of therma

29、lly-induced transverse cracks, and their effect on the initiation of longitudinal cracks, is accounted for in the analysis. The influence of asphalt layer thickness and material parameters is investigated in detail.</

30、p><p>　　Figure 5: Deformation of flexible pavement in the</p><p>　　Vicinity of transverse cracks.</p><p>　　Rock Cutting</p><p>　　The research on rock cutting is aimed at i

31、mproving the bit-rock interaction laws used in dynamic models of drilling systems, and also at developing a methodology to evaluate rock strength from cutting tests. The theoretical and experimental effort is currently f

32、ocused on understanding several basic issues: the conditions controlling the occurrence of brittle and ductile failure in rock cutting (the ductile mode is associated with grains decohesion, the brittle mode with crack p

33、ropagation and chi</p><p>　　Figure 6: Different failure mechanisms occur</p><p>　　in rock cutting depending on the depth of cut : </p><p>　　a ductile mode at small d(larger than the

34、 grain size)</p><p>　　and a brittle mode above a threshold depth </p><p>　　of cut d* .</p><p>　　Figure 7: Numerical simulations of the rock cutting process with the discrete element

35、 code PFC (Itasca Consulting Group) show the</p><p>　　development of cracks and the force chains at the moment of chip formation caused by movement of a cutter.</p><p><b>　　譯 文</b>&

36、lt;/p><p><b>　　解析單元法</b></p><p>　　這項研究的目的是在地下水流在生產(chǎn)工具能夠準(zhǔn)確和高效的區(qū)域系統(tǒng)建模的大型地下水流。這些系統(tǒng)通常由許多含水層,叫做含水層,那相隔漏層能夠抵抗流動,但不是不透水的。進(jìn)入這樣的含水層地下水系統(tǒng)大多數(shù)通過淺表的一層的形式,從降雨入滲。準(zhǔn)確地預(yù)測污染物運動分析的區(qū)域被保護(hù)的（well-head為威爾斯）要求準(zhǔn)確建

37、模的保護(hù)規(guī)劃的地下蓄水層之間的泄漏并通過漏層。</p><p>　　該方法在這個部門開發(fā)等區(qū)域地下水模型的解析元素法。這兩個最重要的應(yīng)用，該方法存在的問題,如上所述,是那種大都會地下水模型(地鐵模型)的友好城市地下水盆地(見http://www.pca.state.mn.us/water/groundwater/metromodel.html),荷蘭NAGROM國家地下水模型。</p><p&

38、gt;　　有限元方法分析的基礎(chǔ)上,針對解析函數(shù)疊加,稱為解析元素,可調(diào),以滿足特定的邊界條件。該方法可應(yīng)用于一般的二維和三維流動問題。目前的研究主要集中在含水層準(zhǔn)確建模漏之間的結(jié)合,在二維和三維元素區(qū)域模式,大,這個所謂的superblock方法,使得有可能創(chuàng)造出非常大的計算機模型能夠產(chǎn)生結(jié)果很快。</p><p>　　二維解析元素的基礎(chǔ)上采用了目前的方法被稱為Wirtinger微積分,它是基于一個變化的變量,它

39、允許所有的分析進(jìn)行了在復(fù)域,無論該矢量場的性質(zhì),它描述了流動。在地下水流動矢量場代表了放電性能的各含水層;這矢量場,也就是說,它的分歧與卷發(fā),依靠自然的流動。選擇解析的元素,使得某些創(chuàng)造一個矢量場,是divergence-free拉普拉斯領(lǐng)域和irrotational(創(chuàng)造),其他的差異,而還有一些的旋轉(zhuǎn)。</p><p>　　圖1:輪廓,恒排量部件彈性介質(zhì)的一致強調(diào)不同</p><p>

40、　　的內(nèi)含物彈性性質(zhì)。利用這些計算等進(jìn)行了較</p><p>　　深入的研究解析單元法,初步開發(fā)了地下水流動。</p><p>　　圖2:占領(lǐng)地帶流線出自形成為一個廢物處置庫。該地區(qū)是包圍著含有廢物漿墻(戰(zhàn)壕里面填滿了資料具有高流動阻力)。在禁區(qū)內(nèi)的一個小好捕捉任何降雨進(jìn)入面積和可能被污染。左邊的人物相適應(yīng)的情況下的墻設(shè)計,而這個數(shù)字是正確地顯示的情況在一個小口,造成顯著存在泄漏發(fā)生。值得

41、注意的是,對于這兩種情況的好平,在最大生產(chǎn)能力以頭井中的屏幕電視機基地的蓄水層。對這些情況的放電故障的長城有200倍,對這些情況完好的墻。</p><p><b>　　聲發(fā)射監(jiān)測</b></p><p>　　一種常見的破壞特征對搖滾的發(fā)展是microcracking,釋放的能量中彈性波的形式被稱為聲發(fā)射(AE)。自動曝光技術(shù)可用來監(jiān)控進(jìn)化的破壞作用,通過全卷,在不同階

42、段的加載。聲發(fā)射的位置提供一幅畫,它形成了一條依據(jù)力學(xué)模型的正當(dāng)性的傷害和失敗。實際上,一個物理解釋的數(shù)據(jù)可以用于定義一個特征長度的層間界面準(zhǔn)脆性材料。建模的反應(yīng)在巖石的特征,局部損傷區(qū)也許是重要的預(yù)測失敗。</p><p>　　圖3:地點了聲發(fā)射大約95%的峰值應(yīng)力</p><p>　　(藍(lán)色)及周邊應(yīng)力峰值(紅色)在一個</p><p>　　梁試驗與庇哩亞砂巖。

43、</p><p>　　或多或少Microcracking是隨機的之前,</p><p>　　但一個局部應(yīng)力峰值區(qū)域可以很明顯</p><p><b>　　地發(fā)現(xiàn),峰值應(yīng)力。</b></p><p><b>　　無損路面表征</b></p><p>　　與我們的高速公路系統(tǒng)日益

44、惡化,他們及時監(jiān)測與維修是必要的。目前,許多地震測試設(shè)備,如:體重下降是可用的非侵入性deflectometer路面的診斷。效力等遙感手段仍是本質(zhì)上的阻礙,然而,用數(shù)據(jù)解釋的難度。在本研究中,一種先進(jìn)的反演計算,設(shè)計開發(fā)了劃分路面路基落錘式彎沉儀的輪廓,從測量。逆解的基礎(chǔ)上提出了一種基于神經(jīng)網(wǎng)絡(luò)方法作為模式識別工具和一個viscoelastodynamic路面模型為預(yù)測裝置。揭露了路面的共振和剛度特性、地面變形數(shù)據(jù)解釋來看合適的頻率響應(yīng)

45、函數(shù)。具有較強的魯棒性,通過反演(i)是提高數(shù)據(jù)采集方案不可或缺,(2)噪聲注射技術(shù)用于神經(jīng)網(wǎng)絡(luò)的發(fā)展,和(3)低通濾波的地震記錄,采用降到最低的掩蔽效應(yīng)的橫向波反射在人行道上的疤痕。</p><p><b>　　圖4:比較的理論</b></p><p>　　頻率響應(yīng)函數(shù),所生產(chǎn)的反分析,與現(xiàn)場</p><p>　　觀測的花明尼蘇達(dá)州的道路測試

46、設(shè)備。</p><p>　　縱向開裂的靈活的人行道</p><p>　　裂紋沿輪路徑(縱向)是最主要的問題在靈活的人行道。這些裂紋在這個崗位上,瀝青面層表面,而且常常終止在到達(dá)基地的人行道上。獲得潛在機制有了深入的縱向裂縫的形成、數(shù)值模擬進(jìn)行代碼ABAQUS使用計算機。將這一實際非均勻和復(fù)雜的正常/剪切輪胎載荷,一個全三維彈性層狀體系得到考慮。</p><p>　　

47、在場的情況下,橫向裂紋,熱致開始他們的影響,是占縱向裂縫對結(jié)果進(jìn)行分析。瀝青面層厚度的影響及材料參數(shù)進(jìn)行詳細(xì)的研究。</p><p>　　圖5:變形的柔性路面橫向裂縫附近。</p><p><b>　　巖石切削</b></p><p>　　該研究對巖石切割的目的旨在提高鉆頭巖石互作用的動態(tài)模型法律用于鉆井系統(tǒng),發(fā)展一個方法來評價巖石強度從切削試

48、驗。理論和實驗的努力是目前集中在理解的一些基本問題:條件控制發(fā)生脆性和球墨鑄鐵失敗在巖石上切割(延展性的模式是用谷物decohesion相關(guān),脆性的模式與裂紋擴(kuò)展和切削);流量特性的失敗的巖石上切割的臉,在刀具、刀具形狀的影響,wearflat在刀具的力量。同時,在球墨政權(quán)進(jìn)行實驗表明,用鋒利的刀具切削力是成正比的橫截面積的減產(chǎn),比例常數(shù),定義為內(nèi)在的特定的能量,是與巖石單軸抗壓強度的提高。</p><p>　　

49、圖6:不同的失效機制發(fā)生</p><p>　　在巖石上切割根據(jù)切削深度:塑性模</p><p>　　式在小d(大于粒度)和一種易碎的模</p><p>　　式的上方,閾值的深度切d*。</p><p>　　圖7:數(shù)值模擬巖石切削過程和離散單元代碼全氟化碳(Itasca咨詢集團(tuán))顯示</p><p>　　裂縫的發(fā)展力的鏈